1. History of the Related Art
It is known that pasty products such as lutes, glues, greases, etc. . . are stored in cartridges or in bags constituted by a supple envelope preferably made of aluminum foil.
European Pat. No. 0052 060 describes a gun intended for discharging the products in question. Such a gun comprises a bored piston disposed in an open cylinder connected to a source of pressurized gas and which in addition ensures tight closure of the base of the cartridge by a rounded peripheral contour.
It will be readily understood that, if the free end of the skirt of the cartridge is damaged, a seal is not ensured, so that an appreciable loss of pressure appears to the detriment of the good general functioning of the gun.
2. Object of the Invention
The improvements forming the subject matter of the present invention aim at overcoming the aforementioned drawback and at allowing production of a piston adapted to ensure tightness either with a cartridge even in the case of a defect in the free edge of its skirt, or with a tubular sleeve in which is placed a charge of pasty product enclosed in a supple envelope.
The invention also aims at providing a free piston which makes it possible to use the tubular sleeve simply by turning over after expulsion of the charge of pasty product.
Finally, the invention aims at a particular tubular structure which allows the use of bellows whose bottom actuates the piston of the cartridge or that of the sleeve in order to avoid any possibility of transfer of compressed gas towards the product to be discharged.